As is known in the art, engine position is conventionally determined using crankshaft position information. The crankshaft position information is typically produced using a toothed wheel with a missing tooth, so that an engine control module can determine relative engine position to each cylinder. However, since the crankshaft rotates twice per engine cycle, information for the crankshaft can only locate engine position to one of two possibilities. To determine the unique engine position, additional information is used. Typically, this information is provided from a cylinder identification (CID) signal coupled to a camshaft. Thus, the engine control module can therefore uniquely determine relative engine position to each cylinder.
During conventional engine starting, the engine control module waits to receive the CID signal before commencing sequential fuel injection, since sequential fuel injection requires unique identification of engine position. In other words, since the CID signal is provided only once per 2 revolutions of the engine, it takes a certain amount of time to uniquely determine engine position. Therefore, there is a certain delay time before sequential fuel injection can commence. Such a system is described in U.S. Pat. No. 5,548,995. Since it can take as many as 2 engine revolution before sequential fuel injection can commence, increased starting time can occur, which degrades customer satisfaction. Conventional approaches in reducing engine start time require injection of fuel using all fuel injectors simultaneously (not sequential), since unique engine position is unknown, and any cylinder may be on an induction stroke drawing in fuel and air. A disadvantage with injecting into all cylinders is that it may be an unfavorable time to receive fuel for some of the cylinders. In particular, it may be a long time until a given cylinder undergoes an induction. The fuel remains in the port area and wets port walls, leading to puddling. Then, when the induction stroke occurs, an inappropriate amount of fuel is inducted, leading to misfire in the extreme and to higher emissions due to poor air-fuel ratio control. To overcome this, one measure is to inject more fuel into all cylinders to ensure there is enough for the leanest cylinder. If engine position can be more quickly determined, it may be possible to reduce the amount of fuel injected into cylinders not currently inducting fuel and air while providing acceptable engine starting times.